This invention relates to a method and apparatus for tufting cut pile fabrics, and more particularly to a method and apparatus for stitching J-tuft pile fabrics.
The tufting of cut pile fabrics by continuously stitching a yarn through a base fabric, forming loops of yarn upon reciprocal hooks, and then cutting the loops held upon the hooks, is well-known in the art.
The tufting of cut pile fabrics having extra long cut pile tufts, known as "shag" carpets is also known, and currently quite popular.
The art of back-robbing or back-drawing previously formed loops in a tufted loop pile fabric is well-known as disclosed in the Dykeman U.S. Pat. No. 1,831,485. Furthermore, the art of back-drawing previously formed loops in accordance with a pattern to form loop pile of different heights is also known as disclosed in the Boyles patent 2,876,441.
The Card U.S. Pat. Nos. 3,084,645; 3,138,126; and 3,075,482 disclose the use of spring clips fixed upon tufting hooks to hold loops formed on the hooks, unless sufficient tension is formed in the loops by back-drawing to pull the loops off the hooks, in order to form tufted fabrics having different pile heights. As a matter of fact, the Card U.S. Pat. No. 3,138,126 discloses an apparatus for tufting a fabric having high and low cut pile.
It has also been a common problem in the tufting industry for many years to eliminate or minimize "J-tufts" in carpeting. A "J-tuft" is a cut pile tuft in which the strands or legs of the cut loops are of unequal heights. Practically, most cut pile comprises "J-tufts" of varying degrees, because the loops of yarn engaged by the tufting hook are cut by the knife on one side of the hook, rather than immediately below the hook, so that inherently a cut pile tuft is formed having unequal strand lengths or heights. Where the strands of the cut pile tuft are too unequal in height, then the appearance of the cut pile carpet is proportionately affected. Thus, where the strands or legs of the tufts are too unequal, the texture or appearance of the cut pile carpet is rough and uneven.
Accordingly, it has been the aim of the tufting industry to reduce or eliminate "J-tufts" from cut pile fabrics, and particularly from cut pile carpets.